Hey guys I’ve done some searching on here but haven’t found any that match my problem. The problem I’m having is that my brakes are locking up but only once air pressure is built up to about 80+. If I bleed the air and then apply the brakes while pressure is building the brakes work as they should. Once the pressure gets around 80 or above and I touch the brakes, they lock up and the pedal no longer has any travel. Bleed the air and you can hear the brakes unlocking. What I’ve read so far is suggesting air pack or master cylinder. Thoughts?